1. Field of the Invention
The present invention relates to a hard disk drive, and more particularly, to a damping structure for a hard disk drive, in which it is provided on a cover of the hard disk drive to alleviate an external shock.
2. Description of the Related Art
A hard disk drive (HDD) is one of the data storage devices in computers that reads data from and/or writes data onto a disk using a read/write head. During the reading and writing operations, the head is shifted to a desired position on the surface of the disk by an actuator, while flying over the recording surface of the spinning disk at a proper height.
FIG. 1 is an exploded perspective view illustrating one example of a conventional hard disk drive, and FIG. 2 is a vertical cross-sectional view of the hard disk drive in FIG. 1.
Referring to FIGS. 1 and 2, the hard disk drive includes a base member 11, a cover member 12, a spindle motor 30 mounted to the base member 11, one or more disks 20, mounted to the spindle motor 30, to store data, and an actuator 40 to move a read/write head to a desired position on the disk 20.
The spindle motor 30 is supported by a flange 31 fixed to the base member 11. A hub 33 is rotatably installed to a shaft 32 of the spindle motor 30 through a bearing 37, and the disk 20 is mounted around an outer periphery of the hub 33. Where a plurality of disks 20 are mounted into the outer periphery of the hub, a ring-shaped spacer 34 is installed around the outer periphery of the hub 33 to uniformly maintain a spacing between the disks 20. A clamp 35 is engaged to an upper end of the hub 33 to prevent the disk 20 from escaping from the hub 33.
The actuator 40 includes a swing arm 42 that is rotatably coupled to a pivot 42 installed to the base member 11, a suspension 46 installed to one end portion of the swing arm 44 for supporting and elastically biasing a slider 48, on which the head is mounted, toward the surface of the disk 20, and a voice coil motor (VCM) 50 to rotate the swing arm 44. The voice coil motor 50 is controlled by a servo control system. The swing arm 44 is rotated in a direction according to the Fleming's left-hand rule by the interaction between an electric current input to a VCM coil and a magnetic field generated by magnets. Specifically, when the disk 20 starts spinning as a result of the hard disk drive being turned on, the voice coil motor 50 rotates the swing arm 44 to move the head to a desired position on a recording surface of the disk 20. On the contrary, when the disk 120 stops spinning by turning the hard disk drive off, the voice coil motor 50 rotates the swing arm 44 to move the head away from the disk 20.
The cover member 12 is assembled to the upper portion of the base member 11 via a plurality of screws 18. A gasket 19 is interposed between the base member 11 and the cover member 12 in order to prevent inflow of a dust or moisture into an interior of the hard disk drive. The gasket 19 is generally made of a viscoelastic material, such as rubber, so that the gasket 19 may damp vibration of the hard disk drive.
The cover member 12 is formed with screw-receiving holes 14 and 15 to correspond to a shaft-fixing screw 16 that is fastened to a shaft 32 of the spindle motor 30 and a pivot-fixing screw 17 that fastened to a pivot 42 of the actuator 40, respectively. The cover member 12 is generally made of an aluminum alloy through die casting. A thin damping plate 60 of stainless steel is adhered to the upper surface of the cover member 12 via a viscoelastic double sided tape 61 in order to reduce a noise generated from the hard disk drive.
Since damping plate 60 is outwardly exposed, with the damping plate 60 being adhered to the upper surface of the cover member 12, a flaw, such as scratch, may occur on the surface of the damping plate 60 in a course of assembling the hard disk drive. This may lead to a deterioration of a quality of the appearance of the hard disk drive.
In order to solve the above problem, therefore, a protrusion 13 is formed along an edge of the cover member 12 in such a manner that the protrusion 13 is protruded by a height C from the upper surface of the damping plate 60.
If the hard disk drive inclines toward the cover member 12 and then falls on a table, the protrusion 13 of the cover member 12 first collides with the table. At this time, an impact load applied to the protrusion 13 is mostly transmitted to the hard disk drive. Specifically, the impact load is transmitted to the spindle motor 30 through the cover member 12 and the shaft-fixing screw 16, resulting in the damage of the bearing 37 and causing the disk 20 to vibrate. In addition, the impact load is transferred to the slider 48 of the actuator 40 through the cover member 12 and the pivot-fixing screw 17. Also, the impact load is transmitted to the base member 11 from the cover member 12 through the screws 18. The impact load is finally transferred to the slider 48 through the actuator 40 installed to the base member 11. As a result, the impact load that is transmitted to the slider 48 causes the slider 48 to vibrate, so that the head mounted to the slider 48 collides with the surface of the disk 20. This head slap phenomenon damages the head and the recording surface of the disk 20 and may bring about an error in the read/write operation of the hard disk drive.